Method for producing thermoplastic resin composition and thermoplastic resin composition

ABSTRACT

It becomes possible to produce a thermoplastic resin composition having a sea-island structure by a kneading step of kneading a thermoplastic elastomer and/or rubber material having an alkoxysilyl group, in which the alkoxysilyl group is grafted to the thermoplastic elastomer and/or rubber material, and a thermoplastic resin in a melt state in a kneading machine and a dynamic crosslinking step of adding a water component into the kneading machine, forming a silanol group by a hydrolysis reaction of the alkoxysilyl group in the thermoplastic elastomer and/or rubber material having an alkoxysilyl group and the water component in the kneading machine, and subsequently forming a siloxane bond by a condensation reaction between the silanol groups.

TECHNICAL FIELD

The present invention relates to a method for producing a thermoplasticresin composition which is excellent in mechanical properties andcolorability and is capable of being molded through remelting, and athermoplastic resin composition.

BACKGROUND ART

Thermoplastic elastomer compositions that are capable of being molded byextrusion molding or injection molding have been used for automobileparts such as a weather strip, a roof molding, and a mud guard,construction materials such as a water blocking material and a jointmaterial, industrial members such as a hose, and the like.

Thermoplastic elastomer compositions include those in whichpolypropylene (PP), ethylene propylene diene rubber (EPDM), oils,crosslinking agents, and the like are blended and dynamic crosslinkingis performed. In the case of complete crosslinking, a phenoliccrosslinking agent is used as the crosslinking agent and, in the case ofpartial crosslinking, a peroxide crosslinking agent is used as thecrosslinking agent (Patent Literatures 1 and 2).

In addition, there is a silanol-crosslinked resin in which a catalystmasterbatch such as tin is mixed with a masterbatch prepared frompolyethylene (PE), a silane coupling agent, and a peroxide (reactioninitiator), and the mixture is molded and is, in the subsequentcrosslinking step, crosslinked with steam, moisture in the air, or thelike (Patent Literature 3).

CITATION LIST Patent Literature

Patent Literature 1: JP-A-5-170930

Patent Literature 2: JP-B-58-46138

Patent Literature 3: JP-A-10-245424

SUMMARY OF INVENTION Technical Problem

However, a thermoplastic elastomer composition (TPV) dynamicallycrosslinked using a phenolic crosslinking agent is excellent inmechanical properties such as compression set due to completecrosslinking, but orange color resulting from phenol appears in moldedarticles and thus there is a problem that the degree of freedom incoloring is low. On the other hand, with regard to TPV dynamicallycrosslinked using a peroxide crosslinking agent, the peroxidecrosslinking agent itself is colorless and transparent and the TPV has ahigh degree of freedom in coloring, but the TPV has a problem that it isinferior in mechanical properties because of partial crosslinking.

In addition, the silanol-crosslinked resin has problems that when oncecrosslinked, the resin cannot be remelted, cannot be remolded, andexhibits a low degree of freedom in molding.

The present invention has been made in view of the above-mentionedpoints, and an object thereof is to provide a method for producing athermoplastic resin composition which is excellent in mechanicalproperties and colorability and is capable of being molded throughremelting and a thermoplastic resin composition.

Solution to Problem

(1) A method for producing a thermoplastic resin composition,comprising:

a kneading step of kneading a thermoplastic elastomer and/or rubbermaterial having an alkoxysilyl group, in which the alkoxysilyl group isgrafted to the thermoplastic elastomer and/or rubber material, and athermoplastic resin in a melt state in a kneading machine; and

a dynamic crosslinking step of adding a water component into thekneading machine, forming a silanol group by a hydrolysis reaction ofthe alkoxysilyl group in the thermoplastic elastomer and/or rubbermaterial having an alkoxysilyl group and the water component in thekneading machine, and subsequently forming a siloxane bond by acondensation reaction between the silanol groups,

wherein the thermoplastic resin composition obtained by the dynamiccrosslinking step has a sea-island structure.

(2) The method for producing a thermoplastic resin composition accordingto (1), wherein in the dynamically crosslinking step,

when the alkoxysilyl group of the thermoplastic elastomer and/or rubbermaterial having an alkoxysilyl group forms the siloxane bond passingthrough the silanol group,

a viscosity of the thermoplastic elastomer and/or rubber material havingan alkoxysilyl group becomes larger than a viscosity of thethermoplastic resin,

the thermoplastic elastomer and/or rubber material having an alkoxysilylgroup undergoes a phase transition to an island structure part of thesea-island structure, and

the thermoplastic resin undergoes a phase transition to a sea structurepart of the sea-island structure.

(3) The method for producing a thermoplastic resin composition accordingto (1) or (2), wherein a gel fraction (in accordance with JIS K 6769:2004/ISO-15875-2: 2003) of the island structure part of the sea-islandstructure is 90% or more.(4) The method for producing a thermoplastic resin composition accordingto any one of (1) to (3), comprising:

in order to prepare the thermoplastic elastomer and/or rubber materialhaving an alkoxysilyl group,

a grafting step of adding and kneading the thermoplastic elastomerand/or rubber material, a silane coupling agent and a reactioninitiator, in a melt state in the kneading machine to graft the silanecoupling agent to the thermoplastic elastomer and/or rubber material,

wherein the grafting step, the kneading step, and the dynamiccrosslinking step are performed continuously in the kneading machine.

(5) The method for producing a thermoplastic resin composition accordingto any one of (1) to (4), wherein the sea structure part of thesea-island structure contains the thermoplastic resin and the seastructure part of the sea-island structure is remeltable.(6) The method for producing a thermoplastic resin composition accordingto any one of (1) to (5), wherein a color difference value: ΔE*ab (inaccordance with JIS Z 8781-4: 2013/ISO 11664-4: 2008) of thethermoplastic resin composition is 1.5 or more, wherein the colordifference value is due to coloring of the thermoplastic resincomposition in the case of blending 0.01 part by weight of a coloringagent relative to 100 parts by weight of the thermoplastic elastomerand/or rubber material.(7) The method for producing a thermoplastic resin composition accordingto any one of (1) to (6), which comprises a thermoplastic resin-addingand kneading step of adding the thermoplastic resin into the kneadingmachine after the dynamic crosslinking step and kneading thethermoplastic resin and the thermoplastic resin composition obtained bythe dynamic crosslinking step.(8) The method for producing a thermoplastic resin composition accordingto any one of (1) to (7), wherein the thermoplastic resin is acrystalline thermoplastic resin.(9) The method for producing a thermoplastic resin composition accordingto any one of (1) to (7), wherein the thermoplastic elastomer and/orrubber material is a thermoplastic elastomer in which the main chain andthe side chains are formed of saturated bonds, and the thermoplasticresin is a thermoplastic resin in which the main chain and the sidechains are formed of saturated bonds.(10) The method for producing a thermoplastic resin compositionaccording to (9), wherein the thermoplastic resin in which the mainchain and the side chains are formed of saturated bonds is anolefin-based resin.(11) The method for producing a thermoplastic resin compositionaccording to (10), wherein the olefin-based resin is apolypropylene-based resin.(12) The method for producing a thermoplastic resin compositionaccording to any one of (9) to (11), wherein the thermoplastic elastomerin which the main chain and the side chains are formed of saturatedbonds is an ethylene/α-olefin-based copolymer.(13) The method for producing a thermoplastic resin compositionaccording to any one of (9) to (12), wherein the color difference value:ΔE*ab (in accordance with JIS Z 8781-4: 2013/ISO 11664-4: 2008) of thethermoplastic resin composition after a weatherable deterioration is 0or more and 3 or less.(14) The method for producing a thermoplastic resin compositionaccording to any one of (1) to (13), wherein the thermoplastic resincomposition is used as a joint material for building materials, a waterblocking material for building materials, an interior material forvehicles, an exterior material for vehicles, or an industrial hosematerial.(15) A thermoplastic resin composition comprising a sea-islandstructure, wherein an island structure part of the sea-island structurecontains a thermoplastic elastomer and/or rubber material cross-linkedby a siloxane bond and a sea structure part of the sea-island structurecontains a thermoplastic resin, and a gel fraction (in accordance withJIS K 6769: 2004/ISO-15875-2: 2003) of the island structure part is 90%or more.(16) The thermoplastic resin composition according to (15), wherein thethermoplastic elastomer and/or rubber material is a thermoplasticelastomer in which the main chain and the side chains are formed ofsaturated bonds, and the thermoplastic resin is a thermoplastic resin inwhich the main chain and the side chains are formed of saturated bonds.

Advantageous Effects of Invention

According to the above (1), since dynamic crosslinking is performedusing a silane coupling agent, there is obtained a thermoplastic resincomposition which has good mechanical properties and colorability,furthermore is capable of being remelted and remolded, and has a highdegree of freedom in molding.

According to the above (9), since a thermoplastic elastomer in which themain chain and the side chains are formed of saturated bonds and athermoplastic resin in which the main chain and the side chains areformed of saturated bonds are used as raw materials and dynamiccrosslinking is performed using a silane coupling agent, there isobtained a thermoplastic resin composition which is excellent inmechanical properties and colorability and is capable of being remeltedand remolded, and has a high degree of freedom in molding and, inaddition, hardly causes a weatherable deterioration.

According to the above (15), since the island structure part of athermoplastic resin composition having a sea-island structure contains athermoplastic elastomer and/or rubber material crosslinked with asiloxane bond and the sea structure part contains a thermoplastic resin,there is obtained a thermoplastic resin composition which has goodmechanical properties and colorability, furthermore is capable of beingremelted and remolded, and has a high degree of freedom in molding.

According to the above (16), since the island structure part of athermoplastic resin composition having a sea-island structure contains athermoplastic elastomer crosslinked with the siloxane bond in which themain chain and the side chains are formed of saturated bonds and the seastructure part contains a thermoplastic resin in which the main chainand the side chains are formed of saturated bonds, there is obtained athermoplastic resin composition which is excellent in mechanicalproperties and colorability and is capable of being remelted andremolded, and has a high degree of freedom in molding and, in addition,hardly causes a weatherable deterioration.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view of a kneading machine in which a graftingstep, a kneading step, and a dynamic crosslinking step are performedcontinuously.

FIG. 2 is a schematic view of a kneading machine in which a graftingstep, a kneading step, a dynamic crosslinking step, and a thermoplasticresin-adding and kneading step are performed continuously.

FIG. 3 is a figure which shows the reaction behavior at the time when analkoxy silyl group is changed into a siloxane bond passing through asilanol group.

FIG. 4 is a table which shows compositions and physical-propertymeasurement results of Examples and Comparative Examples.

FIG. 5 is a table which shows ΔE*ab in terms of NBS unit and sense ofcolor difference.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described. Themethod for producing a thermoplastic resin composition of the presentembodiment has a kneading step and a dynamic crosslinking step, and mayhave a thermoplastic resin-adding and kneading step after the dynamiccrosslinking step.

In the kneading step, the thermoplastic elastomer and/or rubber materialhaving an alkoxysilyl group in which an alkoxysilyl group is grafted tothe thermoplastic elastomer and/or rubber material, and thethermoplastic resin are kneaded in a melt state in a kneading machine.

The thermoplastic elastomer (TPE) to be used in this embodiment is notlimited, and, for example, styrene-based thermoplastic elastomers (TPS),hydrogenated styrene-based thermoplastic elastomers (e.g., hydrogenatedstyrene ethylene propylene-based copolymer (SEP), hydrogenated styreneethylene propylene styrene-based copolymer (SEPS), hydrogenated styreneethylene butadiene-based copolymer (SEBS), etc.), olefin-basedthermoplastic elastomers (TPO), polymerization-type thermoplasticpolyolefin-based elastomers (R-TPO)), vinyl chloride-based thermoplasticelastomers (TPVC), polyurethane-based thermoplastic elastomers (TPU),polyester-based thermoplastic elastomers (TPC), polyamide-basedthermoplastic elastomers (TPA), polybutadiene-based thermoplasticelastomers, fluorine-based thermoplastic elastomers (TPF), and the likecan be used, and one or two or more kind(s) thereof can be used incombination.

The thermoplastic elastomer includes a thermoplastic elastomer in whichthe main chain and the side chains are formed of saturated bonds, andthe thermoplastic elastomer in which the main chain and the side chainsare formed of saturated bonds is a thermoplastic elastomer that does notcontain an unsaturated bond such as a double bond in the main chain andthe side chains. As the thermoplastic elastomer in which the main chainand the side chains are formed of saturated bonds, there may bementioned polymerization-type thermoplastic polyolefin-based elastomers(R-TPO)), polyvinyl chloride-based thermoplastic elastomers (TPVC),fluorine-based thermoplastic elastomers (TPF), and the like, and onekind thereof can be used, or two or more kinds thereof can be used incombination. In particular, the polymerization-type thermoplasticpolyolefin-based elastomers are preferable, and specifically, anethylene/α-olefin copolymer elastomer is mentioned. The copolymerportion of the ethylene/α-olefin copolymer may be either a randomcopolymer or a block copolymer.

The rubber material to be used in the present embodiment is not limited,and for example, natural rubber (NR), isoprene rubber (IR), butadienerubber (BR), styrene butadiene rubber (SBR), butyl rubber (HR), nitrilerubber (NBR), ethylene propylene rubber (EPM), ethylene propylene dienerubber (EPDM), chloroprene rubber (CR), acrylic rubber (ACM), and thelike can be used, and one or two or more kind(s) thereof can be used incombination. In the rubber materials, rubber materials that do notcontain an unsaturated bond such as a double bond in the main chain arepreferable, and ethylene propylene-based rubber (EPM, EPDM), acrylicrubber (ACM), etc. may be mentioned. One kind thereof can be used, ortwo or more kinds thereof can be used in combination.

In the present embodiment, either one of the thermoplastic elastomer andthe rubber material is used alone or both of them are used incombination.

Further, in the case of preparing the thermoplastic elastomer and/orrubber material having an alkoxysilyl group (in the case of using thethermoplastic elastomer in which the main chain and the side chains areformed of saturated bonds, the thermoplastic elastomer having analkoxysilyl group and formed of saturated bonds, the same shall applyhereinafter), the grafting step is performed before the kneading step.

In the grafting step, the thermoplastic elastomer and/or rubbermaterial, a silane coupling agent, a reaction initiator and anappropriate additive are added, and then are kneaded in a melt state ina kneading machine. Thereby, the thermoplastic elastomer composed of thethermoplastic elastomer and/or rubber material having an alkoxysilylgroup is prepared.

The silane coupling agent is used as a crosslinking agent and ispreferably a silane coupling agent having an alkoxysilyl group. As thesilane coupling agent having an alkoxysilyl group, there may bementioned an alkoxysilyl compound having a vinyl group, an alkoxysilylcompound having an epoxy group, an alkoxysilyl compound having an acrylgroup or a methacryl group, etc. and one kind thereof can be used, ortwo or more kinds thereof can be used in combination. In particular, thealkoxysilyl compound having a vinyl group is more preferable because thecompound has good reactivity with the thermoplastic elastomer and/orrubber material and is inexpensive. Specific examples of the alkoxysilylcompound having a vinyl group include vinyltrimethoxysilane,vinyltriethoxysilane, and the like. The blending amount of the silanecoupling agent is preferably 0.1 to 3 parts by weight relative to 100parts by weight of the thermoplastic elastomer and/or rubber material.

As the reaction initiator, dialkyl peroxide-based ones, diacylperoxide-based ones, alkyl perester-based ones, and the like may bementioned, and one kind thereof can be used, or two or more kindsthereof can be used in combination. In particular, dialkylperoxide-based ones are preferable from the viewpoint of the reactivitywith the thermoplastic resin composition and the cost, and specifically,dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy)hexyne-3,2,5-dimethyl-2,5-di (t-butylperoxy)hexane, and the like may bementioned. The blending amount of the reaction initiator is preferably0.01 to 0.5 parts by weight relative to 100 parts by weight of thethermoplastic elastomer and/or rubber material.

Furthermore, it is preferable to blend a silanol crosslinking promotingcatalyst. As the silanol crosslinking promoting catalyst, dibutyltin,fatty acid amides, and the like may be mentioned, and one kind thereofcan be used, or two or more kinds thereof can be used in combination.The blending amount of the silanol crosslinking promoting catalyst ispreferably 0.001 to 0.5 parts by weight relative to 100 parts by weightof the thermoplastic elastomer and/or rubber material.

As the appropriate additives, there may be mentioned reactionterminators, synthetic resin stabilizers such as light stabilizers andantioxidants, processing aids such as lubricants and mold releasingagents, softeners, coloring agents, filling materials (fillers),conductive agents, flame retardants, etc., and they can be blended inthe range where the characteristic of the above-mentioned thermoplasticresin composition is not affected. The reaction initiator, the silanolcrosslinking promoting catalyst, and the appropriate additives may beappropriately mixed into the kneading machine in each step of thekneading step, the dynamic crosslinking step, and the thermoplasticresin-adding and kneading step in addition to the grafting step.

As the reaction terminator (radical scavenger), there may be mentionedcompounds capable of radical scavenging, such as phenolic antioxidantsand hindered amine-based light stabilizers, and one kind thereof can beused, or two or more kinds thereof can be used in combination. Thehindered amine-based light stabilizer is more preferable because thehindered amine-based light stabilizer itself is colorless and excellentin the ability to scavenge radicals. In the case where a phenolicantioxidant is used, there is a grade where the phenolic antioxidantitself is colored, and even if it is a grade where it is not colored,there is a grade where it is colored at the time of processing in akneading machine or the like, so that it is preferable to select a gradewhere it is not colored even when processed in a kneading machine or thelike. In the case of using a grade where it is colored or a grade whereit is colored at the time of processing, it is preferable to use ablending amount that does not affect the colorability of thethermoplastic resin composition. The blending amount of the reactionterminator is preferably 0.01 to 3 parts by weight relative to 100 partsby weight of the thermoplastic elastomer and/or rubber material.

As the synthetic resin stabilizers such as light stabilizers andantioxidants, phenolic antioxidants and hindered amine-based lightstabilizers may be mentioned, and one kind thereof can be used, or twoor more kinds thereof can be used in combination. By blending thesynthetic resin stabilizer, the stability (a weatherable deteriorationand the like) of the thermoplastic resin composition can be furtherenhanced. As the synthetic resin stabilizer, the same compound as thereaction terminator can be used. The blending amount of the syntheticresin stabilizer is preferably 0.01 to 3 parts by weight relative to 100parts by weight of the thermoplastic elastomer and/or rubber material.

As the processing aids such as lubricants and mold release agents, metalsoaps such as erucic acid amides and calcium stearate may be mentioned,and one kind thereof can be used, or two or more kinds thereof can beused in combination. By blending the processing aid, the discharge ofthe thermoplastic resin composition can be stabilized at the outlet of akneading machine such as an extruder, and melt fracture can beprevented. The blending amount of the processing aid is preferably 0.01to 1 part by weight relative to 100 parts by weight of the thermoplasticelastomer and/or rubber material.

As the softeners, paraffin-based oil, olefin-based oil, naphthene-basedoil, aromatic oil, and the like may be mentioned, and one kind thereofcan be used, or two or more kinds thereof can be used in combination.Since the oil itself is colored pale yellow or the like in case of thenaphthen-based oil and the aromatic oil, it is more preferable to useparaffin-based oil or olefin-based oil which is colorless. The blendingamount of the softener can be appropriately adjusted according to thetarget hardness, and is preferably 0 to 150 parts by weight relative to100 parts by weight of the thermoplastic elastomer and/or rubbermaterial.

As the coloring agents, coloring materials such as pigments of variouscolors may be mentioned, and color can be adjusted using one thereof ortwo or more thereof in combination. The coloring agent may be directlyblended in the kneading machine, but it is preferable to use amasterbatch which is excellent in dispersibility and homogeneous anddoes not cause scattering or staining of the kneading machine. Theblending amount of the coloring agent is preferably 0.001 to 3 parts byweight relative to 100 parts by weight of the thermoplastic elastomerand/or rubber material, although it depends on the desired color.

The thermoplastic resin (TP) to be mixed in the kneading step may beeither crystalline or amorphous, or both may be used in combination. Asthe crystalline thermoplastic resin, there may be mentioned olefin-basedresins (PO), polyacetal resins (POM), polyamide-based resins (PA),polyester-based resins (polyethylene terephthalate (PET), polybutyleneterephthalate (PBT), etc.), and the like, as the amorphous thermoplasticresin, there may be mentioned polystyrene-based resins (PS),polycarbonate-based resins (PC), polyvinyl chloride-based resins (PVC),etc., and one kind thereof can be used, or two or more kinds thereof canbe used in combination. The blending amount of the thermoplastic resinis preferably 30 to 300 parts by weight, and more preferably 50 to 200parts by weight relative to 100 parts by weight of the thermoplasticelastomer and/or rubber material.

The thermoplastic resin includes a thermoplastic resin in which the mainchain and the side chains are formed of saturated bonds, and thethermoplastic resin in which the main chain and the side chains areformed of saturated bonds is a thermoplastic resin that does not containan unsaturated bond such as a double bond in the main chain and sidechains. As the crystalline thermoplastic resins in which the main chainand the side chains are forming of saturated bonds, there may bementioned olefin-based resins, polyacetal-based resins, and the like,and as the amorphous thermoplastic resins in which the main chain andthe side chains are formed of saturated bonds, there may be mentionedpolyvinyl chloride-based resins. Moreover, in the case of using anolefin-based resin, a polypropylene-based resin is preferably used.

As the thermoplastic resin to be mixed in the kneading step, acrystalline thermoplastic resin is preferable. This is because, in thekneading step, the thermoplastic elastomer and/or rubber material havingan alkoxysilyl group and the thermoplastic resin are in a melt state,and in the subsequent dynamic crosslinking step, when the alkoxysilylgroup of the thermoplastic elastomer and/or rubber material forms asiloxane bond, a crystalline thermoplastic resin having a clear meltingpoint (Tm) generates a viscosity difference as compared to an amorphousthermoplastic resin having non-clear melting point and hence a phasetransition is likely to occur.

Since the thermoplastic resin mixed in the kneading step is kneaded witha water component in the subsequent dynamic crosslinking step, in thecase of using a hydrolyzable thermoplastic resin (PA, PBT, etc.), it ispreferable to consider the influence of the hydrolysis. This is becausethe molecular weight of the thermoplastic resin is reduced by thehydrolysis reaction, and hence it is also possible to obtain athermoplastic resin composition having improved fluidity and havingmechanical properties such as low rigidity and buckling.

In the case of using a crystalline thermoplastic resin in which the mainchain and the side chains are formed of saturated bonds as thethermoplastic resin to be mixed in the kneading step, hydrolysis of thethermoplastic resin does not occur in the dynamic crosslinking step, andfurther, since the main chain and side chains do not contain anunsaturated bond such as a double bond, it is possible to obtain athermoplastic resin composition that hardly causes a weatherabledeterioration. As the crystalline thermoplastic resin in which the mainchain and the side chains are formed of saturated bonds, olefin-basedresins, polyacetal-based resins, and the like may be mentioned, and onekind thereof can be used, or two or more kinds thereof can be used incombination. As the olefin-based resin (PO), a polyethylene-based resin(PE), a polypropylene-based resin (PP), a polybutene-based resin (PB),and the like may be mentioned. Among the above-mentioned olefin-basedresins, from the viewpoint of heat resistance and moldability of thethermoplastic resin composition, a polypropylene-based resin isparticularly preferable, and may be any of homopolymerization (homo PP)and a copolymer (random PP, block PP).

Incidentally, in the case of using a hydrolysable thermoplastic resin asthe thermoplastic resin and obtaining a thermoplastic resin compositionhaving high mechanical properties, the thermoplastic resin is preferablymixed while dividing the mixing amount of the thermoplastic resinrelative to 100 parts by weight of the thermoplastic elastomer and/orrubber material into the mixing step and the thermoplastic resin-addingand kneading step that is performed in a later step. In thethermoplastic resin-adding and kneading step, the water component mixedin the dynamic crosslinking step is consumed by the hydrolysis reactionor released to the outside of the kneading machine through a vent or thelike, and thus does not exist in the kneading machine. Therefore, thehydrolysis of the added hydrolyzable thermoplastic resin does not occur,and a thermoplastic resin composition having high mechanical propertiescan be obtained.

In the kneading step, in the kneading machine, the thermoplasticelastomer and/or rubber material having an alkoxysilyl group, thethermoplastic resin, and an appropriate additive are added and kneadedin a melt state.

In the dynamic crosslinking step, the water component is added andkneaded. The mixing of the water component into the kneading machine maybe carried out directly as a liquid, or a mixture containing the watercomponent which may be prepared by mixing with a filling material(filler), a water-absorbable polymer, or the like, and the preparedmixture may be blended. In addition, a compound that releases a watercomponent from the compound upon heating or the like, that is a compoundcontaining crystalline water (such as an organic compound, an inorganiccompound, or a mixture of an organic compound and an inorganiccompound), a hydroxide, or the like, may be blended. They can be usedwith one kind, or two or more kinds thereof can be used in combination.Incidentally, the water component is evaporated when the water componentis mixed into a heated kneading machine, and therefore, it is preferableto blend the component in about 1 to 10 times the theoretical blendingamount necessary for changing the alkoxysilyl group into a silanolgroup. The blending amount of the water component is preferably 0.1 to10 parts by weight relative to 100 parts by weight of the thermoplasticelastomer and/or rubber material.

In the dynamic crosslinking step, a hydrolysis reaction is caused bycontacting the alkoxysilyl group of the thermoplastic elastomer and/orrubber material having an alkoxysilyl group with a water componentwherein the thermoplastic elastomer and/or rubber material has so farformed the sea structure part of the sea-island structure, and thus, thealkoxysilyl group is changed into a silanol group. Subsequently, asiloxane bond is formed by the condensation reaction (dehydrationcondensation reaction) between the silanol groups. The alkoxysilyl groupis converted into a silanol group by the hydrolysis reaction, and thesilanol group is further subjected to the condensation reaction to forma siloxane bond, whereby a viscosity of the thermoplastic elastomerand/or rubber material having an alkoxysilyl group is made higher than aviscosity of the thermoplastic resin and hence a phase transition to anisland structure part occurs. On the other hand, in the thermoplasticresin which has so far formed the island structure part of thesea-island structure, a phase transition to a sea structure part occurs.In the dynamic crosslinking step, the thermoplastic elastomer and/orrubber material having an alkoxysilyl group undergoes a phase transitionfrom the sea structure part to the island structure part, and thethermoplastic resin undergoes a phase transition from the islandstructure part to the sea structure part. Thus, the thermoplasticelastomer and/or rubber material having an alkoxysilyl group and thethermoplastic resin are reversed in phase. Thereby, the above-mentionedthermoplastic resin composition is obtained. FIG. 3 shows a reactionbehavior until an alkoxysilyl group forms a siloxane bond passingthrough a silanol group in the case of the thermoplastic elastomerhaving an alkoxysilyl group and formed of saturated bonds.

The thermoplastic resin-adding and kneading step is preferably performedin the case of using a hydrolyzable thermoplastic resin (PA, PBT, or thelike) as the thermoplastic resin. In the dynamic crosslinking step, dueto the water component mixed in, a part of the hydrolyzablethermoplastic resin mixed in the kneading step causes a decrease inmolecular weight and the like due to a hydrolysis reaction with thewater component. However, when the hydrolyzable thermoplastic resin isfurther added in the thermoplastic resin-adding and kneading step, itbecomes possible to reduce the influence of the hydrolysis reaction.Even when the hydrolyzable thermoplastic resin is further added in thethermoplastic resin-adding and kneading step, the thermoplasticelastomer and/or rubber material has already formed the island structurepart of the sea-island structure by the dynamic crosslinking step in theprevious dynamic crosslinking step, and no influence is observed on theisland structure part.

In particular, polyamide-based resins and polyester-based resins (PET,PBT, etc.) are hydrolysable, but are excellent in mechanical propertiesand have a high melting point as compared with olefin-based resins andthe like, and thus a thermoplastic resin composition excellent inmechanical properties and heat resistance can be obtained.

In the thermoplastic resin-adding and kneading step, a thermoplasticresin is added to the thermoplastic resin composition after the dynamiccrosslinking step and is kneaded. The thermoplastic resin to be added inthe thermoplastic resin-adding and kneading step is not limited to thesame type as the type of the thermoplastic resin mixed in the kneadingstep, and may be a different type of thermoplastic resin. The ratio ofthe thermoplastic resin to be mixed in the thermoplastic resin-addingand kneading step is appropriately determined according to thecharacteristics of the target thermoplastic resin composition, but theratio is preferably 15 to 80%, more preferably 40 to 80%, andparticularly preferably 50 to 80% relative to the mixing amount of thethermoplastic resin (total mixing amount) relative to 100 parts byweight of the thermoplastic elastomer and/or rubber material.

The thermoplastic resin composition is formed into pellets, and madeinto automobile parts, water blocking materials, construction materials,industrial members, and the like by known resin molding such asextrusion molding and injection molding. For example, it is used as ajoint material for building materials or a water blocking material forbuilding materials, an interior material for vehicles, an exteriormaterial for vehicles, and an industrial hose material.

The kneading machine 10 shown in FIG. 1 is a kneading machine in whichthe grafting step, the kneading step, and the dynamic crosslinking stepcan be performed continuously in one kneading machine, and is a kneadingmachine suitable for the method for producing a thermoplastic resincomposition of the present embodiment. As the kneading machine, asingle-screw extruder, a twin-screw extruder, a kneading machien, or thelike can be used. In particular, in point of reactive extrudability andself-cleaning properties, a twin-screw extruder is preferable. In thepresent embodiment, explanation is performed using a twin-screw extruderas an example.

The kneading machine 10 is provided, from the upstream side to thedownstream side, with a first zone where the grafting step is performed,a second zone where the kneading step is performed, and a third zonewhere the dynamic crosslinking step is performed, has a structure wherea screw provided inside the cylinder is rotated by a motor M, and thekneaded material is sequentially transferred to the downstream side(first zone second zone→third zone).

In the cylinder, a first supply port 11 is provided in the first zonewhere the grafting process is performed, a second supply port 12 isprovided in the second zone where the kneading process is performed, anda third supply port 13 is provided in the third zone where the dynamiccrosslinking process is performed.

The production of the thermoplastic resin composition performed usingthe kneading machine 10 will be described. From the first supply port11, the thermoplastic elastomer and/or rubber material, the silanecoupling agent, the reaction initiator, and the silanol crosslinkingpromoting catalyst and an appropriate additive which are appropriatelyblended, are supplied into the cylinder and are melt-kneaded in thefirst zone where the grafting step is performed. The alkoxysilyl groupis grafted to the thermoplastic elastomer and/or rubber material bykneading in the first zone to prepare the thermoplastic elastomer and/orrubber material having an alkoxysilyl group, which is transferred to thesubsequent second zone.

In the second zone where the kneading step is performed, thethermoplastic resin and an appropriate additive are supplied into thecylinder from the second supply port 12 and melt-kneaded, and thekneaded material is sent to the next third zone.

In the third zone where the dynamic crosslinking step is performed, thewater component is supplied into the cylinder from the third supply port13 and melt-kneaded. In the kneading in the third zone, a silanol groupis formed by a hydrolysis reaction of the alkoxysilyl group of thethermoplastic elastomer and/or rubber material having an alkoxysilylgroup with the water component, and then forming a siloxane bond by adehydration condensation reaction between the silanol groups. Bychanging the alkoxysilyl group of the thermoplastic elastomer and/orrubber material having an alkoxysilyl group into a siloxane bond, aviscosity of the thermoplastic elastomer and/or rubber material havingan alkoxysilyl group is made higher than a viscosity of thethermoplastic resin. The thermoplastic elastomer and/or rubber materialhaving an alkoxysilyl group which has so far formed the sea structurepart of the sea-island structure undergoes a phase transition to theisland structure part, and the thermoplastic resin which has so farformed the island structure part of the sea-island structure undergoes aphase transition to the sea structure part. The thermoplastic resincomposition is obtained by the phase inversion of the thermoplasticelastomer and/or rubber material having an alkoxysilyl group and thethermoplastic resin. The thermoplastic resin composition extruded fromthe kneading machine 10 is then pelletized by a pelletizer and is usedfor resin molding such as extrusion molding or injection molding.

The kneading machine 10A shown in FIG. 2 is a kneading machine which isprovided with a fourth zone where the thermoplastic resin-adding andkneading step is performed, next to the third zone where the dynamiccrosslinking step is performed in the kneading machine 10 of FIG. 1 andthus makes it possible to perform the grafting step, the kneading step,the dynamic crosslinking step, and the thermoplastic resin-adding andkneading step continuously in one kneading machine, and is a kneadingmachine suitable for the method for producing the thermoplastic resincomposition according to the present embodiment. Incidentally, withregard to the component parts similar to the kneading machine 10 of FIG.1, the same numerals and signs as those of the kneading machine 10 ofFIG. 1 were attached. The kneading machine 10A shown in FIG. 2 has astructure that a screw provided inside the cylinder is rotated by amotor M and the kneaded material are sequentially transferred to thedownstream side (first zone→second zone→third zone fourth zone). Afourth supply port 14 is provided in the fourth zone where thethermoplastic resin-adding and kneading step is performed, and thethermoplastic resin is supplied to the fourth zone from the fourthsupply port and is kneaded. The thermoplastic resin composition kneadedin the fourth zone is then pelletized by a pelletizer and used for resinmolding such as extrusion molding or injection molding.

The thermoplastic elastomer and/or rubber material having an alkoxysilylgroup which was obtained by performing the grafting step in advance, maybe stored. The thermoplastic resin composition having the sea-islandstructure may be prepared through the kneading step and the dynamiccrosslinking step or further through the thermoplastic resin-adding andkneading step by using the stored thermoplastic elastomer and/or rubbermaterial having an alkoxysilyl group at a later date.

The thermoplastic resin composition of the present embodiment may beprepared by using a method other than the above-mentioned productionmethod. For example, first, using the kneading machine 10, athermoplastic elastomer and/or rubber material having an alkoxysilylgroup in which a silane coupling agent is grafted to a thermoplasticelastomer and/or rubber material is prepared. Next, it is molded into aplate or the like, a water component is added, and the alkoxysilyl groupof the thermoplastic elastomer and/or rubber material having analkoxysilyl group and the water component are subjected to a hydrolysisreaction to form a silanol group. Then, a thermoplastic resincomposition crosslinked by a siloxane bond is prepared by a dehydrationcondensation reaction between the silanol groups. In that case, the gelfraction of the thermoplastic resin composition crosslinked by thesiloxane bond is made 90% or more (complete crosslinking). Thereafter,the thermoplastic resin composition crosslinked by the siloxane bond ismade fine by pulverization or the like. For pulverization, a knownpulverizer can be used, and the thermoplastic resin compositioncrosslinked by the siloxane bond may be frozen in advance andfreeze-pulverized, or may be pulverized at room temperature.

Then, using the kneading machine 10, the thermoplastic resin in a meltstate and the finely pulverized thermoplastic resin compositioncrosslinked by the siloxane bond can be kneaded and extruded to obtainthe thermoplastic resin composition of the present embodiment. Afterextrusion, it may be pelletized by a pelletizer and used for resinmolding such as extrusion molding or injection molding. Thethermoplastic resin composition obtained by using the above-mentionedproduction method is excellent in mechanical properties and colorabilityand has a sea-island structure that is capable of molding throughremelting since the remeltable thermoplastic resin constitutes a seastructure part of the sea-island structure and the finely pulverizedthermoplastic resin composition crosslinked by the siloxane bondconstitutes an island structure part of the sea-island structure.

Further, in the thermoplastic resin composition of the presentembodiment, the gel fraction (in accordance with JIS K 6769:2004/ISO-15875-2: 2003) of the island structure part of the sea-islandstructure is preferably 90% or more. Moreover, the color differencevalue: ΔE*ab (in accordance with JIS Z 8781-4: 2013/ISO 11664-4: 2008)is preferably 1.5 or more, wherein the color difference value is due tocoloring of the thermoplastic resin composition of the presentembodiment in the case of blending 0.01 part by weight of a coloringagent relative to 100 parts by weight of the thermoplastic elastomerand/or rubber material. In addition, the color difference value: ΔE*ab(in accordance with JIS Z 8781-4: 2013/ISO 11664-4: 2008) after aweatherable deterioration of the thermoplastic resin composition of thepresent embodiment is preferably 0 or more and 3 or less.

EXAMPLES

Using the following raw materials, the compositions of Examples 1 to 16and Comparative Examples 1 to 6 having the compositions of FIG. 4 wereproduced in a kneading machine. The numerals of individual components inthe compositions of FIG. 4 are shown as parts by weight. Further,Product name: Santoprene 201-64: manufactured by Exxon Mobil Co. forComparative Examples 1 and 2, and Product name: MILASTOMER 7030N:manufactured by Mitsui Chemicals, Inc. for Comparative Example 3 wereused. The kneading machine used was a twin-screw extruder (L/D=72), inExamples 1 to 13 and 16 and Comparative Examples 1 to 6, the kneadingmachine 10 having first to third zones was used, and in Examples 14 to15, the kneading machine 10A having first to fourth zones was used.

With regard to the production conditions in the case of using thekneading machine 10, production was performed as follows: temperature ofthe first zone: 230° C., temperature of the second and third zones: 200°C. for Examples 1 to 12 and 16 and Comparative Examples 1 to 6, andtemperature of the first zone: 230° C., temperature of the second andthird zones: 230° C. for Example 13, screw rotation speed: 400 rpm, anddischarge amount at the outlet: 30 kg/hr.

Further, with regard to the production conditions in the case of usingthe kneading machine 10A, production was performed as follows:temperature of the first zone: 230° C., temperature of the second andthird zones: 270° C., temperature of the fourth zone 270° C. for Example14, and temperature of the first zone: 230° C., temperature of thesecond and third zones: 250° C., temperature of the fourth zone 250° C.for Example 15, screw rotation speed: 400 rpm, and discharge amount atthe outlet: 30 kg/hr.

Incidentally, the temperature of the first zone is appropriately setaccording to the melting points of the raw materials to be used(thermoplastic elastomer, rubber material, etc.) and the degradationtemperature of the reaction initiator to be used and therefore ispreferably 200 to 250° C. as a guideline of the temperature range. Thetemperatures of the second and third zones and the fourth zone arepreferably set to a temperature 10 to 30° C. higher than the meltingpoints of the raw materials (thermoplastic resin etc.) to be used. As aguideline of the temperature range, the temperature is 180 to 230° C. inthe case of TP-1 and TP-5, is 200 to 260° C. in the case of TP-2, is 240to 300° C. in the case of TP-3, and is 220 to 280° C. in the case ofTP-4.

-   -   TPE-1 (olefin-based one): Ethylene/1-octene copolymer,        manufactured by Dow Chemical Co., product name: ENGAGE 8842    -   TPE-2 (styrene-based one): Hydrogenated styrene-based        thermoplastic elastomer (SEBS), manufactured by Clayton Polymer        Japan, Inc., product name: G1651    -   TPE-3 (polyester-based one): Polyester-based thermoplastic        elastomer manufactured by Toyobo Co., Ltd., product name: P-40B    -   Rubber-1: Ethylene propylene diene rubber (EPDM), manufactured        by Dow Chemical Japan Ltd., product name: NORDEL IP 4760P    -   Rubber-2: Acrylic rubber, manufactured by Unimatec Co., Ltd.,        product name: A5098    -   Crosslinking agent (silane coupling agent):        Vinyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co.,        Ltd., Product name: KBM-1003    -   Reaction initiator: Aliphatic organic peroxide, manufactured by        NOF Corporation, product name: Perhexa 25B    -   Reaction terminator-1: Phenolic antioxidant, manufactured by        BASF, product name: IRGANOX 1010    -   Reaction terminator-2: Hindered amine-based light stabilizer,        manufactured by BASF, product name: TINUVIN XT 855 FF    -   Silanol crosslinking promoting catalyst: Octyl tin compound,        manufactured by ADEKA, product name: ADK STAB OT-1    -   Light stabilizer: Hindered amine-based light stabilizer,        manufactured by BASF, product name: TINUVIN XT 855 FF    -   Softener: Paraffin-based process oil, manufactured by Idemitsu        Kosan Co., Ltd., product name: Diana Process Oil PW-90    -   TP-1: Polypropylene-based resin (block type), manufactured by        Japan Polypropylene Corporation, product name: Novatec EC 7    -   TP-2: Polyacetal resin, manufactured by Polyplastics Co., Ltd.,        product name: DURACON M25-44    -   TP-3: Polybutylene terephthalate-based resin, manufactured by        Toray Industries, Inc., product name: TORAYCON 1401X06    -   TP-4: Polyamide-based resin, manufactured by Toray Industries,        Inc., product name: Amilan CM1017    -   TP-5: Polystyrene-based resin, manufactured by CHI MEI        CORPORATION: product name: POLYREX PH-88S    -   Coloring agent: Color master batch, manufactured by Tokyo        Printing Ink Mfg. Co., Ltd., product name: PEX3162 BLUE

Examples 1 to 7 are examples in which the grafting step, the kneadingstep, and the dynamic crosslinking step are continuously performed andthe thermoplastic resin-adding and kneading step is not performed, andin which TPE-1 (olefin-based one) and TP-1 (polypropylene-based resin)are used and the blending amounts and the like of the blendingcomponents are changed. Incidentally, Example 1 is an example in which acoloring agent is not blended, and Examples 2 to 7 are examples in whicha coloring agent is blended. Further, Example 6 is an example in which alight stabilizer is blended and Example 7 is an example in which asoftener is blended.

Example 8 is an example in which the grafting step, the kneading step,and the dynamic crosslinking step are continuously performed and thethermoplastic resin-adding and kneading step is not performed, and inwhich TPE-2 (styrene-based one) and TP-1 (polypropylene-based resin) areused and a coloring agent is blended.

Example 9 is an example in which the grafting step, the kneading stepand the dynamic crosslinking step are continuously performed and thethermoplastic resin-adding and kneading step is not performed, and inwhich TPE-3 (polyester-based one) and TP-1 (polypropylene-based resin)are used and a coloring agent is blended.

Example 10 is an example in which the grafting step, the kneading step,and the dynamic crosslinking step are continuously performed and thethermoplastic resin-adding and kneading step is not performed, and inwhich Rubber-1 (ethylene propylene diene rubber) and TP-1(polypropylene-based resin) are used and a coloring agent is blended.

Example 11 is an example in which the grafting step, the kneading stepand the dynamic crosslinking step are continuously performed and thethermoplastic resin-adding and kneading step is not performed, and inwhich Rubber-2 (acrylic rubber) and TP-1 (polypropylene-based resin) areused and a coloring agent is blended.

Example 12 is an example in which the grafting step, the kneading step,and the dynamic crosslinking step are continuously performed and thethermoplastic resin-adding and kneading step is not performed, and inwhich TPE-1 (olefin-based one) and Rubber-1 (ethylene propylene dienerubber) are used in combination, TP-1 (polypropylene-based resin) isused as a thermoplastic resin and a coloring agent is blended.

Example 13 is an example in which the grafting step, the kneading step,and the dynamic crosslinking step are continuously performed and thethermoplastic resin-adding and kneading step is not performed, and inwhich TPE-1 (olefin-based one) and TP-2 (polyacetal resin) are used anda coloring agent is blended.

Example 14 is an example in which the grafting step, the kneading step,the dynamic crosslinking step, and the thermoplastic resin-adding andkneading step are continuously performed, and in which TPE-1(olefin-based one) and TP-3 (polybutylene terephthalate resin) are usedand a coloring agent is blended. TP-3 (polybutylene terephthalate resin)was mixed in an amount of 20 parts by weight in the kneading step of thesecond zone, and the remaining 50 parts by weight thereof was mixed inthe thermoplastic resin-adding and kneading step of the fourth zone.

Example 15 is an example in which the grafting step, the kneading step,the dynamic crosslinking step, and the thermoplastic resin-adding andkneading step are continuously performed, and in which TPE-1(olefin-based one) and TP-4 (polyamide-based resin) are used and acoloring agent is blended. TP-4 (polyamide-based resin) was mixed in anamount of 20 parts by weight in the kneading step of the second zone,and the remaining 50 parts by weight thereof was mixed in thethermoplastic resin-adding and kneading step of the fourth zone.

Example 16 is an example in which the grafting step, the kneading step,and the dynamic crosslinking step are continuously performed and thethermoplastic resin-adding and kneading step is not performed, and inwhich TPE-1 (olefin-based one) and TP-5 (polystyrene-based resin) areused and a coloring agent is blended.

Comparative Example 1 is an example of phenol crosslinking (completecrosslinking), Comparative Example 2 is an example in which a coloringagent is mixed in Comparative Example 1, and Comparative Example 3 is anexample of peroxide crosslinking (partial crosslinking). ComparativeExample 4 is an example in which the crosslinking agent (silane couplingagent) is not included in the composition of Example 1. ComparativeExample 5 is an example in which the reaction initiator is not includedin the composition of Example 1. Comparative Example 6 is an example inwhich water component is not included in the composition of Example 1.

For each Example and each Comparative Example, there were investigatedthe phase inversion, sea-island structure, maximum value (theoreticalvalue) (parts by weight) of gel component (insoluble matter) of theisland structure part, measured value (parts by weight) of gel component(insoluble matter) of the island structure part, gel fraction (%) of theisland structure part, color difference value (ΔE*ab) due to aweatherable deterioration, color difference value (ΔE*ab) due tocoloring, compression set (%), and remeltability. The results are shownin FIG. 4. The color difference value (ΔE*ab) due to a weatherabledeterioration was measured in Examples 1 to 7 and Comparative Examples 1to 6.

The presence or absence of the phase inversion and the presence orabsence of the sea-island structure were confirmed through preparationof a thin film with an ultramicrotome (FC6: manufactured by Leica) andobservation with a transmission electron microscope (H-7650:manufactured by Hitachi High-Technologies Corporation).

The maximum value (theoretical value) of the gel component (insolublematter) of the island structure part is the blending amount (100 partsby weight) of TPE or rubber.

The measured value of the gel fraction of the island structure part wasobtained in accordance with JIS K 6769: 2004. JIS K 6769: 2004 is astandard corresponding to ISO 15875-2: 2003.

The gel fraction (%) of the island structure part was calculated from[(Measured value (parts by weight) of gel component (insoluble matter)of island structure part/Maximum value (parts by weight) of gelcomponent (insoluble matter) of island structure part)×100].

The color difference value (ΔE*ab) due to a weatherable deteriorationwas measured with a color difference meter (SM color computer SM-T:manufactured by Suga Test Instruments Co., Ltd.) in accordance with JISZ 8781-4: 2013. JIS Z 8781-4: 2013 is a standard corresponding to ISO11664-4: 2008. The color difference value (ΔE*ab) due to a weatherabledeterioration is a color difference of the thermoplastic resincomposition before and after the weatherable deterioration.Incidentally, the weatherable deterioration test was performed inaccordance with JIS K 7350-2: 2008 B method, by irradiation with a xenonlamp at irradiance: 150 W/m² (wavelength region of 300 to 400 nm) underthe conditions of a cumulative irradiation amount: 300 MJ/m² and a blackpanel temperature: 63±3° C. using a light-resistance testing machine(SC-700FP: manufactured by Suga Test Instruments Co., Ltd.). JIS K7350-2: 2008 is a standard corresponding to ISO 4892-2: 2006.

The color difference value due to coloring, with regard to thecolorability (color developing property) depending on the blending ornon-blending of the coloring agent, was measured in accordance with JISZ 8781-4: 2013, similarly to the above-mentioned color difference valuedue to a weatherable deterioration. The color difference value (ΔE*ab)due to coloring is a color difference value of the thermoplastic resincomposition resulting from the blending of the coloring agent.Incidentally, the color difference values due to the coloring inExamples 2 to 16 and Comparative Examples 3 to 6 were measured relativeto Example 1 (non-blending of coloring agent) and the color differencevalue due to the coloring in Comparative Example 2 was measured relativeto Comparative Example 1 (non-blending of coloring agent). The largerthe value of ΔE*ab is, the better the colorability is.

Color difference value: ΔE*ab is defined as the Euclidean distancebetween coordinates in CIE 1976 L*a*b* color space, and indicates thecolor difference between two color stimuli calculated by the followingequation.

ΔE*ab=[(ΔL*)²+(Δa*)²+(Δb*)²]^(1/2)

Also, the color difference value: ΔE*ab can be, as shown in FIG. 5,represented by the NBS unit and the sense of color difference(evaluation of the degree of sensory color difference) which are definedby the U.S. Bureau of Standardization. The numerical values in thecolumn of the NBS unit in FIG. 5 are values of ΔE*ab calculated from theabove equation.

The compression set was measured in accordance with JIS K 6262: 2013 Amethod (70° C.×22 h, 25% compression). JIS K 6262: 2013 is a standardcorresponding to ISO 815-1: 2008 and ISO 815-2: 2008.

With regard to the remeltability, hot pressing was performed at 180° C.for 3 minutes for each Example and each Comparative Example, and thepresence or absence of melting was confirmed. The case where it wasmelted was evaluated as “O” and the case where it was not melted wasevaluated as “x”.

In Examples 1 to 16, the phase inversion was “Yes”, the sea-islandstructure was “Yes”, and the gel fraction of the island structure partwas 92 to 99%. Further, in Examples 1 to 16, the compression set was assmall as 29 to 40%, and the remelting property was “0”. Incidentally, inthe case of the use for automobile parts, water blocking materials,construction materials, industrial members, etc., the compression set ispreferably 50% or less and more preferably 40% or less. In Examples 1 to16, the gel fraction of the island structure part is 92 to 99% andcomplete crosslinking is achieved by using a silane coupling agent, thusthe compression set is as low as 29 to 40%, and they can be suitablyused as automobile parts, water blocking materials, constructionmaterials, industrial members, and the like.

With regard to the colorability, when Example 1 and Example 2 werecompared, the color difference value (Δ*abE) due to coloring in the caseof blending 0.01 part by weight of the coloring agent relative to 100parts by weight of TPE-1 was 5, the NBS unit was located between 3.0 and6.0, and the sense of color difference was at a noticeable level, sothat the colorability was excellent. Further, also for Examples 3 to 16,as compared with Example 1, the color difference value due to coloringwas 4 to 6 and the colorability was excellent as Example 2.

Moreover, although not shown in FIG. 4, hardness was measured forExample 1 and Example 7 (softener-blended example). When Example 1 andExample 7 were compared, the hardness of Example 1 was D60 (measured bya type D durometer), and the hardness of Example 7 was A65 (measured bya type A durometer). Thus, the hardness of the thermoplastic resincomposition can be lowered while maintaining the characteristics such asthe color difference value due to coloring and the compression set. Thehardness was measured in accordance with JIS K 6253-3: 2012. JIS K6253-3: 2012 is a standard corresponding to ISO 7619-1: 2010.

In Examples 1 to 7 using a thermoplastic elastomer in which the mainchain and the side chains are formed of saturated bonds, the colordifference value (ΔE*ab) due to a weatherable deterioration was 2.1 to2.8, and the color difference value due to a weatherable deteriorationwas small.

Comparative Example 1 is an example in which a thermoplastic elastomer(EPDM) having a double bond in the side chain is crosslinked withphenol, and the phase inversion was “Yes”, the sea-island structure was“Yes”, the gel fraction of the island structure part was 100%, thecompression set was as small as 33%, and the remeltability was “0”.

In Comparative Example 1, since EPDM is used, the color difference value(ΔE*ab) due to a weatherable deterioration was 13.2, and thus the colordifference value due to a weatherable deterioration was large.

Comparative Example 2 is an example in which a coloring agent is blendedin Comparative Example 1, and the phase inversion was “Yes”, thesea-island structure was “Yes”, the gel fraction of the island structurepart was 100%, the compression set was as small as 35%, and theremeltability was “O”. When Comparative Example 1 and ComparativeExample 2 are compared, the color difference value (ΔE*ab) due tocoloring in the case of blending 0.01 part by weight of the coloringagent relative to 100 parts by weight of Santoprene 201-64 was 0.8, theNBS unit was located between 0.5 and 1.5, and the sense of colordifference was at a slightly felt level, which was inferior to the colordifference value (ΔE*ab) of 5 due to coloring in Example 2. Thisindicates that the phenol itself used for the phenol crosslinking has acolor tone and the colorability is low even when a coloring agent isblended. When the blending amount of the coloring agent is increased,the color difference value (ΔE*ab) due to coloring of thephenol-crosslinked thermoplastic resin composition can be increased, butit becomes difficult to color it lightly. In particular, in the CIE 1976L*a*b*color space, it is very difficult to lightly color thephenol-crosslinked thermoplastic resin composition in the color oppositeto the color of the phenolic crosslinking agent itself. Accordingly, thethermoplastic resin composition of the present Example can be colored ina light color while a phenol-crosslinked thermoplastic resin compositionis difficult to color in such a color, and it is indicated that thecomposition of the present Example is excellent in the degree of freedomin coloring.

In Comparative Example 2, since EPDM is used, the color difference value(ΔE*ab) due to a weatherable deterioration was 14.2, and thus the colordifference value due to a weatherable deterioration was large.

Comparative Example 3 is an example in which a thermoplastic elastomer(EPDM) having a double bond in a side chain is crosslinked with aperoxide, and the phase inversion was “Yes”, the sea-island structurewas “Yes”, the gel fraction of the island structure part was 60%, thecompression set was as large as 52%, and the remeltability was “0”.Comparative Example 3 had a color difference value (ΔE*ab) due tocoloring of 6 and was excellent in colorability, but the islandstructure part of the thermoplastic resin composition was crosslinked(partially crosslinked) by the peroxide crosslinking agent, so that thegel fraction of the island structure part was low, and the compressionset was large.

In Comparative Example 3, since EPDM was used, the color differencevalue (ΔE*ab) due to a weatherable deterioration was 12.5, and thus thecolor difference value due to a weatherable deterioration was large.

Comparative Example 4 is an example in which a crosslinking agent(silane coupling agent) was not blended, and the phase inversion was“No”, the sea-island structure was “No”, and the compression set was aslarge as 88%, and remeltability was “0”. Since crosslinking did notoccur, the gel fraction of the island structure part was not able to bemeasured. Comparative Example 4 has a color difference value (ΔE*ab) dueto coloring of 5 and is excellent in colorability, but the islandstructure part is not crosslinked and the compression set is large, sothat it is not suitable for automobile parts, water blocking materials,construction materials, industrial members, and the like. The reason whythe remeltability of Comparative Example 4 is “0” is that the obtainedthermoplastic resin composition is a mixture of TPE-1, P0-1, and thelike and has thermoplasticity.

Comparative Example 4 uses raw materials formed of saturated bonds, sothat the color difference value (ΔE*ab) due to a weatherabledeterioration was 2.7, and thus the color difference value due to aweatherable deterioration was small.

The comparative example 5 is an example in which a reaction initiatorwas not blended, and the phase inversion was “No”, the sea-islandstructure was “No”, and the compression set was as large as 90%, andremeltability was “0”. Since crosslinking did not occur, the gelfraction of the island structure part was not able to be measured.Comparative Example 5 has a color difference value (ΔE*ab) due tocoloring of 4 and is excellent in colorability, but the island structurepart is not crosslinked and the compression set is large, so that it isnot suitable for automobile parts, water blocking materials,construction materials, industrial members, and the like. The reason whythe remeltability of Comparative Example 5 is “0” is that the obtainedthermoplastic resin composition is a mixture of TPE-1, P0-1, and thelike and has thermoplasticity.

Comparative Example 5 uses raw materials formed of saturated bonds, sothat the color difference value (ΔE*ab) due to a weatherabledeterioration was 2.4, and thus the color difference value due to aweatherable deterioration was small.

The Comparative Example 6 is an example in which a water component wasnot blended, and the phase inversion was “No”, the sea-island structurewas “No”, and the compression set was as small as 12%, but remeltabilitywas “X”. Comparative Example 6 had a color difference value (ΔE*ab) dueto coloring of 5 and was excellent in colorability, but since remeltingwas impossible, it was not able to be remolded and had a low degree offreedom in molding. The reason why the compression set of ComparativeExample 6 was small is that the obtained thermoplastic resin compositioncaused overall crosslinking without forming a sea-island structure, andthe resin composition was not a thermoplastic resin composition havingan island structure, and therefore, remolding through remelting was notable to be performed.

Comparative Example 6 uses raw materials formed of saturated bonds, sothat the color difference value (ΔE*ab) due to a weatherabledeterioration was 2.5, and thus the color difference value due to aweatherable deterioration was small.

Thus, the thermoplastic resin compositions obtained by Examples of thepresent invention are excellent in colorability and mechanicalproperties, and can be remolded by remelting, so that they are suitablefor automobile parts, water blocking materials, construction materials,and industrial members. Furthermore, the use of a thermoplasticelastomer in which the main chain and side chains are formed ofsaturated bonds can make a weatherable deterioration less likely tooccur.

In one aspect of the present invention, an object is to provide athermoplastic resin composition which is excellent in mechanicalproperties and colorability, is capable of molding through remelting,and in addition, hardly causes a weatherable deterioration, in useapplications requiring weatherability such as automobile parts, waterblocking materials, construction materials, industrial members, and thelike. As one of technical means for solving the object, a method forproducing a thermoplastic resin composition which has the followingcharacteristics can be mentioned.

<Characteristics>

A method for producing a thermoplastic resin composition, comprising:

a kneading step of kneading a thermoplastic elastomer having analkoxysilyl group and formed of saturated bonds, in which thealkoxysilyl group is grafted to the thermoplastic elastomer wherein themain chain and the side chains are formed of saturated bonds, and athermoplastic resin wherein the main chain and the side chains areformed of saturated bonds, in a melt state in a kneading machine; and

a dynamic crosslinking step of adding a water component into thekneading machine, forming a silanol group by a hydrolysis reaction ofthe alkoxysilyl group in the thermoplastic elastomer having analkoxysilyl group and formed of saturated bonds and the water componentin the kneading machine, and subsequently forming a siloxane bond by acondensation reaction between the silanol groups,

wherein the thermoplastic resin composition obtained by the dynamiccrosslinking step has a sea-island structure.

The present invention has been described in detail with reference toparticular embodiments, but it will be apparent to those skilled in theart that various changes and modifications can be made without departingfrom the spirit and scope of the present invention.

The present application is based on Japanese Patent Application No.2017-064300 filed on Mar. 29, 2017 and Japanese Patent Application No.2017-235926 filed on Dec. 8, 2017 and the entire contents areincorporated herein by reference. Also, all the references cited hereinare incorporated as a whole.

1. A method for producing a thermoplastic resin composition, comprising:a kneading step of kneading a thermoplastic elastomer and/or rubbermaterial having an alkoxysilyl group, in which the alkoxysilyl group isgrafted to the thermoplastic elastomer and/or rubber material, and athermoplastic resin in a melt state in a kneading machine; and a dynamiccrosslinking step of adding a water component into the kneading machine,forming a silanol group by a hydrolysis reaction of the alkoxysilylgroup in the thermoplastic elastomer and/or rubber material having analkoxysilyl group and the water component in the kneading machine, andsubsequently forming a siloxane bond by a condensation reaction betweenthe silanol groups, wherein the thermoplastic resin composition obtainedby the dynamic crosslinking step has a sea-island structure.
 2. Themethod for producing a thermoplastic resin composition according toclaim 1, wherein in the dynamically crosslinking step, when thealkoxysilyl group of the thermoplastic elastomer and/or rubber materialhaving an alkoxysilyl group forms the siloxane bond passing through thesilanol group, a viscosity of the thermoplastic elastomer and/or rubbermaterial having an alkoxysilyl group becomes larger than a viscosity ofthe thermoplastic resin, the thermoplastic elastomer and/or rubbermaterial having an alkoxysilyl group undergoes a phase transition to anisland structure part of the sea-island structure, and the thermoplasticresin undergoes a phase transition to a sea structure part of thesea-island structure.
 3. The method for producing a thermoplastic resincomposition according to claim 1, wherein a gel fraction (in accordancewith JIS K 6769: 2004/ISO-15875-2: 2003) of the island structure part ofthe sea-island structure is 90% or more.
 4. The method for producing athermoplastic resin composition according to claim 1, comprising: inorder to prepare the thermoplastic elastomer and/or rubber materialhaving an alkoxysilyl group, a grafting step of adding and kneading thethermoplastic elastomer and/or rubber material, a silane coupling agentand a reaction initiator, in a melt state in the kneading machine tograft the silane coupling agent to the thermoplastic elastomer and/orrubber material, wherein the grafting step, the kneading step, and thedynamic crosslinking step are performed continuously in the kneadingmachine.
 5. The method for producing a thermoplastic resin compositionaccording to claim 1, wherein the sea structure part of the sea-islandstructure contains the thermoplastic resin and the sea structure part ofthe sea-island structure is remeltable.
 6. The method for producing athermoplastic resin composition according to claim 1, wherein a colordifference value: ΔE*ab (in accordance with JIS Z 8781-4: 2013/ISO11664-4: 2008) of the thermoplastic resin composition is 1.5 or more,wherein the color difference value is due to coloring of thethermoplastic resin composition in the case of blending 0.01 part byweight of a coloring agent relative to 100 parts by weight of thethermoplastic elastomer and/or rubber material.
 7. The method forproducing a thermoplastic resin composition according to claim 1, whichfurther comprises a thermoplastic resin-adding and kneading step ofadding a thermoplastic resin into the kneading machine after the dynamiccrosslinking step and kneading the thermoplastic resin and thethermoplastic resin composition obtained by the dynamic crosslinkingstep.
 8. The method for producing a thermoplastic resin compositionaccording to claim 1, wherein the thermoplastic resin is a crystallinethermoplastic resin.
 9. The method for producing a thermoplastic resincomposition according to claim 1, wherein the thermoplastic elastomerand/or rubber material is a thermoplastic elastomer in which the mainchain and the side chains are formed of saturated bonds, and thethermoplastic resin is a thermoplastic resin in which the main chain andthe side chains are formed of saturated bonds.
 10. The method forproducing a thermoplastic resin composition according to claim 9,wherein the thermoplastic resin in which the main chain and the sidechains are formed of saturated bonds is an olefin-based resin.
 11. Themethod for producing a thermoplastic resin composition according toclaim 10, wherein the olefin-based resin is a polypropylene-based resin.12. The method for producing a thermoplastic resin composition accordingto claim 9, wherein the thermoplastic elastomer in which the main chainand the side chains are formed of saturated bonds is anethylene/α-olefin-based copolymer.
 13. The method for producing athermoplastic resin composition according to claim 9, wherein the colordifference value: ΔE*ab (in accordance with JIS Z 8781-4: 2013/ISO11664-4: 2008) of the thermoplastic resin composition after aweatherable deterioration is 0 or more and 3 or less.
 14. The method forproducing a thermoplastic resin composition according to claim 1,wherein the thermoplastic resin composition is used as a joint materialfor building materials, a water blocking material for buildingmaterials, an interior material for vehicles, an exterior material forvehicles, or an industrial hose material.
 15. A thermoplastic resincomposition comprising a sea-island structure, wherein an islandstructure part of the sea-island structure contains a thermoplasticelastomer and/or rubber material cross-linked by a siloxane bond and asea structure part of the sea-island structure contains a thermoplasticresin, and a gel fraction (in accordance with JIS K 6769:2004/ISO-15875-2: 2003) of the island structure part is 90% or more. 16.The thermoplastic resin composition according to claim 15, wherein thethermoplastic elastomer and/or rubber material is a thermoplasticelastomer in which the main chain and the side chains are formed ofsaturated bonds, and the thermoplastic resin is a thermoplastic resin inwhich the main chain and the side chains are formed of saturated bonds.